/Engine/Plugins/Online/OnlineSubsystem/Source/Public/Interfaces/OnlineChatInterface.h
Get cached list of chat messages for a currently joined chat room
true if found
bool GetLastMessages ( const [FUniqueNetId](API\Runtime\CoreOnline\Online\FUniqueNetId) & UserId, const [FChatRoomId](API\Plugins\OnlineSubsystem\Interfaces\FChatRoomId) & RoomId, int32 NumMessages, [TArray](API\Runtime\Core\Containers\TArray)< [TSharedRef](API\Runtime\Core\Templates\TSharedRef)< [FChatMessage](API\Plugins\OnlineSubsystem\Interfaces\FChatMessage) > > & OutMessages )